Document boost fail if a field copy omit the norms

Details

Description

After https://issues.apache.org/jira/browse/LUCENE-3796, it is not possible to set a boost to a field that has the "omitNorms" set to true. This is making Solr's document index-time boost to fail when a field that doesn't omit norms is copied (with copyField) to a field that does omit them and document boost is used. For example: